Patents on Audio Software and File Formats

Index of Select Patents on Audio Software and File Formats

Microsoft "ASF" Patent

  • 6,041,345. Microsoft obtained a patent on the ASF (Active Stream Format) audio file format on March 21, 2000. The patent is entitled: "Active stream format for holding multiple media streams."

    Here is the abstract:

    An active stream format is defined and adopted for a logical structure that encapsulates multiple data streams. The data streams may be of different media. The data of the data streams is partitioned into packets that are suitable for transmission over a transport medium. The packets may include error correcting information. The packets may also include clock licenses for dictating the advancement of a clock when the data streams are rendered. The format of ASF facilitates flexibility and choice of packet size and in specifying maximum bit rate at which data may be rendered. Error concealment strategies may be employed in the packetization of data to distribute portions of samples to multiple packets. Property information may be replicated and stored in separate packets to enhance its error tolerance. The format facilitates dynamic definition of media types and the packetization of data in such dynamically defined data types within the format.

    Microsoft forced Avery Lee, a free software developer to revoke support for the ASF format from his "VirtualDub" GPL-ed video editing/capture program. Here is Mr. Lee's description of his encounter with Microsoft (from Advogato article, referenced below):

    "Today I received a polite phone call from a fellow at Microsoft who works in the Windows Media group. He informed me that Microsoft has intellectual property rights on the ASF format and told me that, although I had reverse engineered it, the implementation was still illegal since it infringed on Microsoft patents."
    Linux World News aptly commented on the effect of file-format patents on the future of free software (article referenced below):

    "Microsoft is claiming patent protection on a file format. It is not at all hard to see what could happen with an extension of that claim. Any serious word processor in the commercial world has to be able to cope, somehow, with the numerous variations of Microsoft's Word format. If that format were to come under patent protection, programs like StarOffice, ApplixWare, and WordPerfect could lose the ability to work with Word files. That would not bode well for their future market share.

    Intellectual property laws increasingly look like the tool of choice for those who wish to fight against free software. The ability to patent file formats, if it stands up, adds greatly to the power of this weapon. This is a worrisome development indeed."

    Also see:

    IBM's "Network Delivery" Patent

  • 6,195,693. This is IBM's "Method and system for network delivery of content associated with physical audio media" patent, filed on November 18, 1997 and granted on February 27, 2001. Here is the abstract:

    A method and system in a multimedia computer system for automatically retrieving and presenting data associated with an audio recording having unique identifying indicia therein. In response to playing an audio recording in a multimedia computer system, a unique identifying indicia associated with the audio recording is identified. A listing of codes within the multimedia computer system is automatically searched to find a code corresponding to the unique identifying indicia. In response to finding the code corresponding to the unique identifying indicia, multimedia data is retrieved which corresponds to the unique identifying indicia. The multimedia data can be retrieved from local storage or from a remote network site. The multimedia data corresponding to the unique identifying indicia is then presented in the multimedia computer system, while playing the audio recording in the multimedia computer system.


    IBM's '693 patent covers a method "in a multimedia computer system for automatically retrieving and presenting data associated with an audio recording" (claim 1). According to the claims, the patented method appears to cover the following process:

    - Storing an "unique identifying indicia" on an audio CD according to the Red Book Audio CD standard. This identifier is stored on the CD, but separate from the audio content.
    - Reading the unique identifier from an audio CD when such a CD is put into a computer and/or played;
    - Searching for information associated with the CD's unique identifier from a "listing of codes ... located at a remote network site."
    - Retrieving "multimedia data," (for instance, lyrics, song lists, pictures of the band, etc.) corresponding to the audio CD's unique identifier from a remote database;

    Fraunhofer MP3 Patents

    Fraunhofer IIS-A (a German research organization) and Thomson Multimedia have several patents related to the MP3 standard of audio compression. Thomson Multimedia manages the licensing of these patents. Currently, Thomson collects patent royalties from the developers of MP3 encoding/decoding software. Here is the Thomson /Fraunhofer Patent Portfolio, which includes patents granted in several countries. Here are links to several of the U.S. Patents.

    MP3 Standards and the Fraunhofer Patents

    The MP3 specification - ISO/IEC 11172-3, entitled "Coding of moving pictures and associated audio for digital storage media at up to about 1,5 Mbit/s -- Part 3: Audio" - is an ISO standard that was developed based on Fraunhofer's work. "MP3: The Definitive Guide" by Scott Hacker (published by O'Reily) is an excellent source of information on this topic. Additionally,'s Patents and MP3 page explains the relationship between the Fraunhofer patents and the MPEG standards-setting process.

    "Many people think that the MP3 standard is free and open, and that the ISO reference source code is also. But in the beginning of September 98, Fraunhofer Institute, largely involved in the development of MPEG-audio compression, has send a letter to several developers of "free" ISO-source based encoders. In this letter they make it very clear that all developers and publishers of MPEG-audio layer 3 (MP3) encoders based on ISO-source must pay a license fee to Fraunhofer."

    Potential Legal Issues Associated with Fraunhofer's Patents

    Ogg Vorbis is an free software alternative to MP3, licensed under the GNU General Public License. According to the Ogg Vorbis FAQ, it "is different from these other formats because it is completely free, open, and unpatented." A December 11, 2000 CNET News article (referenced below) illustrated the potential legal problems faced by the Ogg Vorbis developers.

    "The Ogg developers staunchly defend the notion that they have created everything from scratch, or at least have built their system without using any of the Fraunhofer-owned technology. But their rivals say they aren't so sure.

    "We doubt very much that they are not using Fraunhofer and Thomson intellectual property," Linde said. "We think it is likely they are infringing."

    Whether this is true, analysts say Thomson and the German company are likely to file patent lawsuits the moment Vorbis appears to be a viable market candidate. By creating a perception of uncertainty around Vorbis' future, MP3's parents could prevent conservative digital music companies from adopting it."

    Also see:

    Questions, comments and suggestions to Vergil Bushnell

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